An explosion has damaged a gas pipeline in Moldova, cutting supplies to some eastern European nations by about 40 per cent.

The "accident" occurred on Wednesday in the country's breakaway Transdniestr region.

The blast caused a crater measuring more than 110sq metres and could be heard 10km away, Liliana Puscasu, a spokesman for the region's emergency situations department, said.

"This accident ... is linked to the fact that the age of this pipeline has exceeded 30 years," the de facto interior ministry of Transdniestr said on its website.

Gazprom, the Russian gas supplier, regularly suffers from supply disruptions due to the age of pipelines and other equipment across the former Soviet Union.

"The volume of the gas reduction is around 40 percent. Gas deliveries are being carried out through parallel gas pipelines," Gazprom said in a statement.

The blast destroyed one of the three pipelines used to supply natural gas to the Balkans.

Official hopeful

Angel Semerdzhiev, Bulgartransgaz chief executive, said it usually took up to three days for repairs to be carried out, but he was hopeful that deliveries to Bulgaria and the Balkans would be restored "soon".

Bulgaria receives all of its gas from Russia via Ukraine, Moldova and Romania, and also sends it ons to neighbouring Turkey, Greece and Macedonia.

Several of those countries also reported supply shortages on Wednesday.

Semerdzhiev promised that Bulgarian consumers would not be affected, since Bulgartransgaz would use reserves from its underground storage facility in northwestern Bulgaria to compensate for reduced supplies.

He did not say if Bulgaria was still pushing gas through to the countries further down the transit route.

Gazprom said it would increase deliveries to Turkey through the Blue Stream link under the Black Sea to compensate for any problems.

Bulgaria, which lacks any access to alternative gas sources or routes, was among the countries worst affected by a row between Russia and Ukraine in January that left much of eastern Europe without supplies in the depths of winter.